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Unread 12-17-2014, 11:41 AM
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Fair! Fair! is offline
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Join Date: Jul 2004
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Default Re: Vorshlag Scion FR-S LSx Alpha Project

Project Updates for Dec 17th, 2014: A lot has happened with this project - and at Vorshlag - since my last post in this thread. There should have been about 2 or 3 updates since then, but I'm horribly behind on updating project threads, so you guys get a BIG one today. Vorshlag has been busy with new shop construction, a move to a new space twice as large, adding fabrication equipment and CNC machines, going to SEMA/OUSCI, etc. Our service shop has been cranking out race car builds, custom suspension/chassis/aero/safety upgrades for various track cars as well as production work. I talk a little more about the shop move and SEMA in this recent Alpha Miata LS1 update (link).

We are really pushing to complete this FR-S V8 project. Luckily we already have lot of initial parts development completed with this car Alpha build, and we should be able to produce our typical "Stage 0" kit sometime early in 2015. Stage 0 is usually - motor mounts, transmission crossmember, oil pan, headers, and driveshaft. We will also have the front drive accessories, most of the cooling system parts, and maybe a few other items completed and ready to go to production by Spring. We will then fine tune production solutions for "everything else" on the next "Beta" build - wiring, gauge integration, fuel system, etc.

Drivetrain Mounting Solution

Last time we checked in on this Alpha build we were wrapping up the transmission crossmember and attacking the motor mounts. We really made two sets of mounts, but somebody didn't follow my instructions and the first set was tossed straight into the trash. A second set was made properly and this pair + all of the pieces to the transmission crossmember were removed, finished welded, cleaned up and powder coated gloss black in early August.

The transmission crossmember assembly is shown above, with the motor mounts next to these parts and all of the hardware needed shown. There are also two reinforcement plates on the inside of the tunnel that we will add, similar to what we did on the Alpha Miata V8. The final powder coated parts were installed onto the car after they were photographed in our little in-house photo studio.

The motor mounts have the proven polyurethane bushing used in 100+ LS1 swaps built by Vorshlag since there was no reason to reinvent the wheel. The transmission mount busing is also something we've used many times, and we make this in both 95A durometer polyurethane or in a harder Nylon material for pure race cars. These design features have been used on both street and race applications and the polyurethane bushings damp engine vibrations well while keeping drivetrain movement to a minimum. The Vorshlag motor mounts (shown below) bolt into existing holes in the crossmember and have massive exhaust header room.

These are near-production ready versions, with the major aspects and mounting points positioned right where we want them. This means the drivetrain is now set in the car where we designed it to be - after many iterations, measurements, and discussions - so the shifter location, drive line angles, fore-aft placement, left-right and up-down positioning are all locked down. We have scanned these final prototype bits and from that data we have made CAD designs with about 3 revisions in SolidWorks. The production versions of these parts will be made from CNC laser cut plate pieces that will be altered ever so slightly for repeatable volume production. We will make production welding fixtures during the Beta build.

With the drivetrain locations set we could move to the next big phase of this swap - construction of the exhaust headers.

Long Tube Header Development

This is a huge step, and usually the biggest challenge for home-built engine swaps, but it is something we have done many times. The prototype FR-S swap headers were completed a couple of months ago. Let's go back look at the process so than I can explain how we go about making one-off and production exhaust headers in a cost effective way, with zero compromises to the fit, performance or quality.

We have a certain set of rather expensive header development tools we use on these engine swaps that allows us to make multiple primary tube routings very quickly, which cuts down on development time and leads to a better final layout. The prototype process still took over 50 hours for this first pair of headers, even with an experienced fabricator and all of the trick tools.

First we acquired 304 Stainless Steel exhaust port flanges and 3" merge collectors, then a big box of stainless mandrel bends in 1.75" diameter. We used our production header supplier to source these parts, so they would match the production CNC bender's sizing for this sized primary tube. The flanges were bolted to the cylinder heads and the collectors were placed where they were appropriate. These were locked down in place with temporary brackets tack welded to the collectors and bolted to the chassis, with proper ground clearance as well as the best primary tube length distances.

Next, four primary tubes at a time were laid out up in the plastic mock-up tooling and many iterations of these tubes were tested until the best routing and packaging were made with the least number and severity of bends. This takes many hours and a lot of clicking and unclicking of these orange plastic bits - but its kind of fun seeing it all come together. Eventually the most logical routing is decided on and that process is complete.

The hardest side to do is always the driver's - to route around the steering shaft, which always seems to be right in the way. As the final four tubes are completed in plastic, each one is turned into stainless steel tubes and mandrel bends, tack welded (or taped) together, perfectly matching the plastic mock-up tubes in length, diameter, bend radius, and angle of cut.

While it looks like we work from the top down, its really the collector that dictates a lot of the constraints, and that's where the focus usually lies - and around the steering shaft. The wide engine bay of the FT86 gives us liberal room to make nice, straight runs out of the exhaust port before turning, which we almost never get to do on most swaps. This should mean we will see at least the typical power gains over LSx exhaust manifolds that we usually get with our V8 swap headers.

The passenger side went much more quickly since nothing was in the way. We did round up an air conditioning compressor and bracket first, to make sure the primary tube routing up front was clear, but that proved to not be much of an issue with the final accessory drive set-up we chose (see more below). We also had sourced a new LSx starter and mounted it to the mock-up engine, as the passenger side set of tubes needed to route around that with as much room as possible - to avoid heat soaking the attached starter solenoid.

Once routing aspects were perfected, each tube was tack welded at each junction, then removed and fully seam welded at each joint. These 8 completed prototype primary tubes were then tack welded to the exhaust flanges and merge collectors. Again, this entire process took over a week of solid work (53.5 hours, to be exact). Some of the extra time comes from trying to make these reproducible - knowing the distance between bends that the CNC bender's clamps can make - but even one-off headers usually take 40-50 hours to make for a V8.

The final layout we ended up with follows the contours of the chassis, which dictates a lot of the shape of the final product, but it also uses good fabrication, the best materials, and proper header design to maximize power gains. Our previous LS1 swap headers have proven to pick up 40-50 wheel horsepower over stock manifolds or worse, the block hugger shorty header designs some folks use on these swaps - because making one off custom headers that flow well is so difficult.

Although we could have sent the headers off with the tubes just tack welded together at the many junctions, Olof seam welded each tube. Why? To be able to get this car back on the road quicker than normal for a typical Alpha swap development timeframe of 12-18 months. Once these prototype tubes return we will finish weld them and get this set ready to go into this car. The customer met with us today and wants his set ceramic coated, so we'll have that process added to his set as well.

Our crew carefully packaged and shipped the final prototype FRS LSx headers (above) to our US header manufacturer, who then made a production fixture from that set, then blew apart each assembly into individual tubes. They then measured and modeled each tube and replicated all eight in CNC bent tubes, then they put together a pre-production header assembly and sent it to us for testing. The passenger side fit perfectly on the first try but we just received and tested the 2nd production iteration for the driver's side and it is almost perfect. We just have a few small interferences to work out around the steering shaft.

continued below

Last edited by Fair!; 12-19-2014 at 07:43 PM.
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